Department of Neurological Surgery, University of California, San Francisco, 94143, USA.
J Neurosurg. 2011 Feb;114(2):386-93. doi: 10.3171/2010.5.JNS10256. Epub 2010 Jun 18.
Vestibular schwannomas (VSs) are benign lesions with an unpredictable natural history. Perhaps the greatest barrier to predicting which patients need treatment is our poor understanding of how these tumors cause hearing loss in the first place. In this case-control study, the authors investigated the relationship between preoperative hearing loss and histological changes such as intratumoral microhemorrhage and extensive fibrosis.
From a prospectively collected database, the authors selected all patients with VS who had undergone microsurgical resection as their initial treatment for histopathologically confirmed VS. Histological specimens obtained in 274 of these patients were systematically reviewed by a blinded neuropathologist who graded the extent of microhemorrhage and fibrosis in these tumors. The effect of these variables on preoperative hearing loss was studied using binary logistic regression.
On univariate analysis, patients with extensive intratumoral microhemorrhage or fibrosis (p < 0.0001), patients with larger tumors (p < 0.05), and patients 65 years of age or older (p < 0.05) were significantly more likely to have unserviceable hearing at the time of surgery. On multivariate analysis, only patients with extensive intratumoral microhemorrhage or fibrosis had an increased risk of having unserviceable hearing at the time of surgery (OR 3.72, 95% CI 1.3-10; p = 0.01). Older age and tumor size greater than 3 cm were not statistically significant risk factors for hearing loss, controlling for the effect of microhemorrhage and fibrosis.
In this study, the authors have demonstrated a correlation between the extent of nonneoplastic histological changes, such as microhemorrhage and fibrosis, and hearing loss. This alternate hypothesis has the potential to explain many of the exceptions to previously described mechanisms of hearing loss in patients with VS. The advent of high-resolution MR imaging technology to identify microhemorrhages may provide a method to screen for patients with VS at risk for hearing loss.
前庭神经鞘瘤（VSs）是一种良性病变，其自然病史不可预测。也许预测哪些患者需要治疗的最大障碍是我们对这些肿瘤首先导致听力损失的机制缺乏了解。在这项病例对照研究中，作者研究了术前听力损失与肿瘤内微出血和广泛纤维化等组织学变化之间的关系。
作者从一个前瞻性收集的数据库中选择了所有接受显微手术切除的 VS 患者作为其最初的治疗方法，这些患者的组织病理学均证实为 VS。对 274 名患者的组织学标本进行了系统回顾，由一名盲法神经病理学家对这些肿瘤中微出血和纤维化的程度进行分级。使用二元逻辑回归研究这些变量对术前听力损失的影响。
在单因素分析中，广泛的肿瘤内微出血或纤维化患者（p < 0.0001）、肿瘤较大的患者（p < 0.05）和 65 岁或以上的患者（p < 0.05）在手术时更有可能出现无法使用的听力。在多因素分析中，只有广泛的肿瘤内微出血或纤维化患者在手术时出现无法使用的听力的风险增加（OR 3.72，95%CI 1.3-10；p = 0.01）。在控制微出血和纤维化的影响后，年龄较大和肿瘤大小大于 3 cm 不是听力损失的统计学显著危险因素。
在这项研究中，作者已经证明了非肿瘤性组织学变化的程度（如微出血和纤维化）与听力损失之间存在相关性。这种替代假说有可能解释许多以前描述的 VS 患者听力损失机制的例外情况。高分辨率磁共振成像技术的出现可以识别微出血，为筛选有听力损失风险的 VS 患者提供一种方法。
